1. Field of the Invention
The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus that transmits light to an electronic image sensor via an image fiber to capture images.
2. Description of the Related Art
Various imaging apparatuses employ a configuration in which light incident from an imaging optical system is transmitted through an image fiber and an electronic image sensor captures images. For example, apparatuses such as a fluorescent imaging apparatus, an industrial weak light detecting apparatus, or an astronomical observation apparatus use techniques for amplifying weak light with the aid of an image fiber to obtain high-brightness images.
A moire pattern occurs in an image captured by transmitting light incident from an imaging optical system to an electronic image sensor through an image fiber. Two causes can be thought of as the causes of the moire pattern. One of the causes is non-uniform sensitivity resulting from a difference between the types and cycles of the lattice of the electronic image sensor and the lattice of the image fiber. Japanese Patent Application Publication No. H9-312385 proposes a method of reducing a moire pattern resulting from the non-uniform sensitivity remarkably by employing a configuration in which the angle between the lattice of photoelectric transducers and the lattice of optical fibers is between 10° and 20°.
The other cause is the difference between the cycle of sensor pixels and the cycle of fiber pixels. A radiographic imaging apparatus disclosed in Japanese Patent Application Publication No. 2012-200455 proposes a configuration in which a scatter removing grid (corresponding to the image fiber) in which radiation absorbing materials are arranged in a grid form is inclined with respect to a radiation detector so as to satisfy a condition determined from the frequency of an imaging segment. By inclining the grid so as to satisfy the condition, it is possible to shift a moire pattern to a frequency region higher than the frequency of the imaging segment and to prevent the occurrence of the moire pattern.